Lock-joint flooring.



JAMES w. GRAY, or Tacoriawasniveroim LOCK-JOINT FLOORING.

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Specification of Letters Patent.

Patented Get. if?, 1916.

Application ined August 10, i915. y serial No. 44,740.

contiguous edges of the boards are cut.

The objects of the invention are to Vprovide such a shape as willeliminate the defects in the common tongue-andgroove form at present inuse; especially, preventing the vertical sliding and creaking' of oneboard past the adjacent board between the sup'- ports, providing a tightjoint between said boards even though the boards mayshrink apartslightly, allowing for a greater depth of wear in the upper' surface ofthe boards without VVreducing the strength of the joint, increasing thestrength of the joint, providing a form which will not be easily injuredwhen it is being nailed in place, providing a means whereby one board onbeing fasteneddowii locks the joint between it and the adjacent boardagainst vertical movenient, providing` a joint which may be put togethereven though the boards may be slightly swollen by dampness, andVvproviding a shape whichitself pi'otects'its wearing edges from injurywhen beingA shipped. I attain these and other objects by .the devicesand arrangements illustrated in the accompanying drawings, in which-Figure l is a section on an enlarged scale of a` strip of myimpi'ovedflooring showing it in position in relation to lthe adjacent board onone side and showing the edges ofthe Ynent adjacent board on the otherside being inserted in place;Fig. 2 is a perspective view showing partsof'two boards laid to form a floor; Fig. 3 is asection of one of myimproved flooring `.boards showing the Vnail passing therethrough andinto the supporting joist; Fig. 4 is an end elevation of a floor beinglaid illustrating how a board which has been slightly swollen is laid;and l? ig. 5 is an end elevation showing a number of boards as they arestacked and secured together for shipment. i. y y

Similar numerals of reference refer to similar parts throughout theseveral views.

YReferring to the construction illustrated inthe drawings The top orwearing surf face l-is madeof standard width from edge` Y y to edge andthe lower or .bearing surface 2 is slightly narrower. One side of theboard is provided with a lip while the other is provided withacorresponding recess. Referring first to the side having the lip, we

will follow its course from the wearing surAv face l to the bearingsurface `2. This side' leaves the surface l at a right-angle, asat 3,but curves outward on a circular arc 4,

forininga vconcave surface which extends to the endvof the lip 5; thenit passes vertically downward a short distance, as at 6, thus formingthe end of the lip;l then it passes'v inwardon a linev 7 which isinclined about 3 degrees downward from the horizontal, said line 7passing inward about twice the distance thatthe linee extends outwardfrom the edge 3, thus undercutting the said edge `3 and forming thetightening under surface of the lip 5; then it passes toY theI bearingsurface 2, preferably following an inclined outward direction, as at 8,so that the Vlower edge 9 thereof is substantially under the upper edge3; ,Y

Similarly the side having the recess therein leaves the edge l0,.opposite to the above mentioned edge 3, of the wearing surface l on aconvex circular are 11, leaving said surface l at a right-angletherewith, and

passes inward-fon said curved line l1 until faces 4 and llwarealso incontact. `Also the surface 1B is made at the same' angle as the surface7 4 so that whenthey touch they will contact along a wide surface. Theshoulder and 13 .will come in vcontact with each other before thesurfaces 4 and 11 meet (see leftion I13 -is however veryslightlyy raisedrelatively 4to the said line 7 so that the two' surfaces 7.

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hand of Fig. 1,)fandalso the surfacel is slightlynarrower than thesurface?Y Then 1 the surfacer14 joins theA end of the surface l'with the`side 2, being'parallel .with 'but slightly separated from the side 78,`above described, and forming anobtuseangle 15 with :the said side 2.This angle 15V is almost under the angle 10 but is very slightlyundercut therefrom. The sides 13 and 14k join in an angle 1G and thisangle projects outward from the edge 10 a distance substantially equalto the, distance that the curvev which are substantially as wide as thepresent tongue-and-groove construction, but that each said part extendsout only one-half its Vtotal width and the boards are undercut onlyone-half the amount of the present groove and that therefore all theparts of the joint are stronger than iii the tongueand-grooveconstruction. The lip 5 extends out only one-half as far as a tongue andit cannot be readily split from the board because its upper surfaceextends on a curve to the wearing surface 1 of the board,`thus forming aroot of substantially twice the thickness of the usual tongue, while theundercut side-7 is so slight as to be substantially no weaker than thesolid board: the recess overhang at 10 is only one-lialf the overhang ofthe parts forming the ordinary groove and the depth is substantially thesame, while its shape forms a cantaliver ably stronger, both under loadand in resistance to damage, than the tongue-andgroove joint. Also itmust be observed that this board can be cut from about zlinch less widthof stock than the corresponding size of tongue-and-groove construction,thus makinga great saving in material thereover. f

A oor islaid by first nailing one board down, lip edge out, driving thenails 17 on aninclined line (Fig. 3) through the concave surface 4:.Then the shoulder 13 ofk the next board is inserted under the lip V5thus nailed. The said shoulder engages the lip before the board isforced home into position (Fig. 1) and then the board is thus forcedinto position and nailed as above. Now, the slight incline to thesurfaces 7 and 13 has been such as to put the parts under strain whenthe boards are forced into contact at their edges 3 and 10', theshoulder 13 supporting the lip 5 and the surface 4 of the lip 5supporting the cantaliver 11, so that the joint between the boards isAno weaker between supports than are the boards themselves, hence therewill be no vertical motion between the boards when loaded between thesupports since they are eectually interlocked in tight contact with eachother. lf the lip 5 or the shoulder 13 should become swollen by dampnessbefore *1 laying,

then the new board is inserted by tipping its edge as shown in Fig. 4L.1f the boards shrink after laying7 the joint will be stronger andVstiffer than the tongue-andgroove because the surfaces 7 and 13 willremain in contact throughout their length but with slightly less width,so that the lip edge will be supported by the recess edge of theadjacent board, but there will be a slight motion permitted if thegreater strain is on the recess edge of the board, though even then themotion will be no greater than occurs in the usual tongue-andgrooveboards at present in use.

An additional advantage on my improved boards is found in the fact thanwhen they are bundled, as shown in Fig. 5, the wearing edges 3 and 10,which it is important should be kept in perfect condition, are protectedbyy integral projections, 5 and 16 respectively, which prevent anycontact with said edges to damage them. This feature is not found in thetongue-and-groove form since the edge in which the groove is made has nointegral projection to protect it from dam- Although flooring has beenmentioned throughout the above description it is to be understood that Ido not confine myself to flooring but to any form of boards 'i Havingdescribed my invention, what l claim as new is:

1. A lock joint for flooring and the like u comprising in combination awooden member having an outwardly and downwardly inclined surfaceleading from the top surface thereof, said inclined surface beingadapted to receive a holding nail, a substantially horizontal surfaceforming with said inclined surface a projecting lip, said substantiallyhorizontal surface, however being` inclined somewhat downwardly andinwardly, a third surface connecting said substantially horizontal:surface with the underside of the member, said third surface and saidsubstantially horizontal surface forming a substantial recess beneathsaid lip, and a second member having surfaces compleinental to said.first mentioned and said second mentioned surfaces, a recesscomplemental to said lip, and a lip for projecting into the recessbeneath said first Vmentioned lip, the substantially horizontal surfacesof the two members wedgingjtogether to firmly hold the second memberagainst the support, the lip on said second member being of materiallyless length than the recess in said tends from the edge of the wearingsurface the remainder of said side surface extending outward from theinner end of said undercut on an inclined line to the bearing surface ofsaid strip; and having the opposite side surface complementarily formed.

3. A lock joint for flooring and the like comprising in combination awooden member having an outwardly and downwardly inclined surfaceleading from the top surface thereof, said inclined surface beingAadapted to receive a holding nail and forming a slightly extending lip,said lip terminating in a narrow vertical surface near the center of theedge of said member, the underside of said lip being undercut on adownwardly inclined line extending inward. from said vertical surface, athird surface extending from the inner end of said undercut to the underside of the member and thusI forming a recess beneath said lip, and asecond member having surfaces complemental to said first mentionedmember except as to said central vertical surface of said lip, and saidsecond mentioned member having a lip projecting into said recess butbeing materially shorter than said recess, whereby a iirm wedgingengagement is obtained between the two members irrespective of swelling.

4L. A lock joint for flooring and the like comprising in combination awooden member having an outwardly and downwardly inclined surfaceleading from the top surface thereof, said inclined surface beingadapted to receive a holding nail, a substantially horizontal surfaceforming with said inclined surface a projecting lip, said substantiallyhorizontal surface, however, being inclined somewhat downwardly andinwardly to form a wedging surface, a third surface connecting saidsubstantially horizontal surface near the under side of the member',said third surface and said substantially horizontal surface forming arecess beneath said lip, said substantially horizontal surface extendinginwardly a greater distance than said first mentioned surface extendsoutwardly, and a second member having surfaces complemental to saidfirst mentioned and said second mentioned surfaces, a recesscomplemental to said lip, and a lip for projecting into the recessbeneath said iirst mentioned lip, the substantially horizontal surfacesof the two members wedging together to iirmly hold the second memberagainst the support, and the lip on said second member being ofmaterially less length than the recess in said first mentioned memberwhereby a strong wedging engagement is insured irrespective of swelling.

JAMES W. GRAY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents Washington, D. C.

